The standard concept of PFC (Power Factoring Correction), has been for years concerned with the phase shift between voltage and current, since this parameter developed besides the Real Power (measured in Watt), a Reactive Power (measured in VAR); a kind of power that, although didn't use energy, it increased the total current carried on the power line, engaging more generators and all intermediate equipments (step up and step down transformers, etc.).
However, the problem was immediately solved, because it was caused by a reactive component of inductive nature (see Table-A—Sec. Effect of an Inductive Load), which was easily compensated by a reactive component of the same value, out of phase in inverse nature (capacitive), connected to the user end (power factor correction of the system).
The users with a typology of nonlinear current absorption, considerably help to modify, this “normal” functional condition, lacking in harmonic distortions (therefore easily resolvable); three classic examples are:                Gas-discharge lamps;        Partial loads on each phase (with SCR/TRIAC controls);        power supply, generally.        
Therefore, there is a group of users, connected to the distribution network, whose real problem of correction, is not to introduce a phase shift between voltage and current (a problem easy to solve), but to introduce, on the network itself, a large quantity of harmonics, which the users connected produces in intrinsic mode.
Table-A in the Sec. “Harmonic Distortions for some kind of users”, points out exactly some loads with this kind of problem. The table shows, for each one of them, both the graph of the current, and the quantization of its more considerable harmonics (analysis in the time-and-frequency-domain); the cases described are:                a neon glow lamp (the phenomenon is similar for all gas-discharge lamps)        a typical single-phase power pack (without PFC);        a typical three-phase power pack (without PFC).        
That is, of course, a serious problem they tried to reduce through several rules; in Europe, for instance, Rule no EN-61003 Is in force. Its limits (under particular conditions of power/use) are reported in Table-B—Sec. Rule EN61003.
Therefore the cited rule doesn't succeed in solving the problem, but it can only reduce its extent. And, as electronics-of-energy-conversion becomes more and more competitive (motor controls with VVVF systems, Energy-Conversion with PWM technique), and, consequently, the number of harmonics introduced on the network rises up, the same problem expands, and the “Quality of the Waveform Supplied to the User” is more and more reduced (see Table B—Sec. “Typical graph of the voltage for distorted currents”).
The present invention is based on the following concerns:                the production of alternative electric energy of small/medium power, integrated on the feeding external network;        the conversion/use of energy with PWM technique systems. Therefore, the problem exits (see Table-B —Sec. “Examples of optimal waveforms that compensate the harmonic distortion in generation/use”) of establishing whether it is advantageous/useful, to a generator/user not to operate with sinusoidal currents, but with exactly distorted currents, able to correct the harmonic distortions on the network.        
Our project is able to:                supply, on the concerned distribution tracts, and with all the advantages this produces, a “qualitatively” better energy.        give to the alternative-energy converters (working with PWM technique), also a correcting/improvement factor in the waveform's quality, for the power line to which they are connected;        improve the performances of the users (working with PWM technique), so that they are no more the cause of wave distortion, but of the correction/improvement of the wave itself.        
Table-B—Sec. “Examples of optimal waveforms that compensate the harmonic distortion in generation/use”), describes, in a preliminary way (later on, we'll face the technical point of view), how that can be realized, in fact:                the first graph shows an half cycle of voltage, with a typical wave's distortion, pointing out the error which characterizes it, compared with the theoretical value it should have;        the second graph shows the optimal distortion a generator should have, when, connected to a power line, it has to mitigate the harmonic distortions on the power line itself. In that case, as it is described in the graph, it should generate a small energy on the lower values of the sinusoid, and concentrate it on the higher amplitudes, exactly where the waveform is lowered;        finally, the third graph shows the optimal distortion a user should have when, connected to a power line, it has to mitigate the harmonic distortions that are on the power line itself. In that case, as the graph points out, it should absorb a great deal of energy on the low values of the sinusoid, and reduce it on the higher amplitudes, exactly where the waveform is lowered;        